Apparatus for blowing high-temperature reducing gas into blast furnace

ABSTRACT

An apparatus for blowing high-temperature reducing gas into a blast furnace comprising a device for settling the supply amounts of raw materials such as hydrocarbons, a raw material controlling device to control the supply amounts of hydrocarbons, oxygen (or air) and steam to a cracking furnace according to the signal of said supply amount settling device, a furnace pressure gauge provided in the blast furnace, a cut-off valve for branch pipe gas, a pressure control valve provided in a reducing gas exhaust pipe line, a producer gas pressure gauge provided in an inlet pipe line of said pressure control valve, and an indicator controller to calculate and instruct the degree of opening of said pressure control valve according to the signals from said supply amount settling device, the furnace pressure gauge and the producer gas pressure gauge, and also calculate and instruct the opening and closing of the cut-off valve for branch pipe gas.

United States Patent Hara et al.

[ APPARATUS FOR BLOWING HIGH- TEMPERATURE REDUCING GAS INTO BLAST FURNACE [72] Inventors: Yoshiaki Hara; Akio Masagaki; Masaaki lguchi, all of l-limeji, Japan [73] Assignee: Nippon Steel Corporation, Tokyo,

Japan 221 Filed: April2l, 1971 21 Appl.No.: 136,073

[30] Foreign Application Priority Data May 28, 1970 Japan ..45/45830 [52] US. Cl. ..266/29 [51] Int. Cl ..F27b l/28 [58] Field of Search ..266/29; 75/42 [56] References Cited UNITED STATES PATENTS 2,420,398 5/1947 Kinney ..75/42 2,719,083 9/ i955 Pomykala ..75/42 51 Sept. 19, 1972 3,189,438 6/1965 Von Bogdandy ..266/29 Primary Examiner-Gerald A. Dost Attorney-Toren & McGeady [5 7] ABSTRACT An apparatus for blowing high-temperature reducing gas into a blast furnace comprising a device for settling the supply amounts of raw materials such as hydrocarbons, a raw material controlling device to control the supply amounts of hydrocarbons, oxygen (or air) and steam to a cracking furnace according to the signal of said supply amount settling device, a furnace pressure gauge provided in the blast furnace, a cut-off valve for branch pipe gas, a pressure control valve provided in a reducing gas exhaust pipe line, a producer gas pressure gauge provided in an inlet pipe line of said pressure control valve, and an indicator controller to calculate and instruct the degree of 2 Claims, 1 Drawing Figure PATENTEDSEPIQ m2 3.692.293

INVENTORS YosHlAHl HGQRA Amo MASA m BY HASAAKI IGUCIHI Tmm 0 M1" APPARATUS FOR BLOWING HIGH- TEMPERATURE REDUCING GAS INTO BLAST FURNACE This invention relates to an apparatus for blowing high-temperature reducing gas into a blast furnace under a stabilized condition.

in recent years, various means have been proposed for the purpose of improving the productivity of the blast furnace. As an example, a method of blowing high-temperature reducing gas, which is produced in a cracking furnace by cracking, at a high temperature, hydrocarbons (such as natural gas, heavy oil, petroleum naphtha, light oil and lamp oil) blown into the furnace together with oxygen (or air) and steam, into a blast furnace from an injector of the furnace is under industrialization.

In this instance, while the amount of hydrocarbons, oxygen (or air) and steam should be controlled in accordance with the amount of reducing gas blown into the blast furnace, the amount of reducing gas to be blown into the blast furnace differs with the furnace condition of the blast furnace. Moreover, as the furnace pressure of the blast furnace fluctuates every moment, it is necessary to control the blowing-in pressure of the gas in accordance with said fluctuation. When the control of the supply of reducing gas in answer of fluctuating the blast furnace pressure is not sharp enough, the reaction in the blast furnace is altered and no smooth operation of the blast furnace can be continued, and consequently the improvement in the productivity of the blast furnace is impossible.

Said relationship is most earnestly required when the pressure reduction or the cease operation of the blast furnace becomes necessary owing to the occurrence of a certain trouble of the blast furnace.

In the pressure reduction of a usual blast furnace, the blowing-in pressure of air is reduced in a few minutes suddenly to a desired blowing-in pressure. However, this pressure reduction can seldom be carried out intentionally with a sufficient time. Therefore, in the case of blowing high temperature reducing gas into a blast furnace, the blowing-in of the gas should be controlled promptly in answer of said requirements.

When said control is delayed and a large amount of high-temperature reducing gas is blown into a blast furnace under pressure reduction, not only the furnace reaction is disturbed but also the operation of pressure reduction is delayed, causing various troubles on the furnace operation. On the other hand, when this control is not stabilized and the blowing-in pressure of the gas becomes lower than the pressure of the blast furnace under pressure reduction, there occurs such troubles in the reducing gas system that the blast furnace gas flows backward into a high-temperature supply pipe line, depositing a large amount of fine dust in the pipe line, and in some instances the cracking of hydrocarbons in the cracking furnace becomes impossible.

This invention offers an apparatus for blowing hightemperature reducing gas into a blast furnace under a stabilized condition, eliminating said troubles. The essential points of the invention are:

1. An apparatus for blowing high-temperature reducing gas into a blast furnace comprizing a device for settling the supply amounts of raw materials such as hydrocarbons a raw material controlling device to control the supply amounts of hydrocarbons, oxygen (or air) and steam to a cracking furnace according to the signal of said'supply amount settling device, a furnace pressure gauge provided in the blast furnace, a pressure control valve provided in a reducing gas exhaust pipe line, a producer gas pressure gauge provided in an inlet pipe line of said pressure control valve, and a controller to calculate and instruct the degree of opening of said pressure control valve according to the signals from said supply amount settling device, the furnace pressure gauge and the producer'gas pressure gauge; and

2. an apparatus for blowing high-temperature reducing gas into a blast furnace comprising a device for settling the supply amounts of raw materials such as hydrocarbons, a raw material controlling device to control the supply amounts of hydrocarbons, oxygen (or air) and steam to a cracking furnace according to the signal of said supply amount settling device, a computer to settle the pressure of producer gas by hand, a furnace pressure gauge provided in the blast furnace, a pressure control valve provided in a reducing gas exhaust pipe line, and a producer gas pressure gauge provided in an inlet pipe line of said pressure control valve.

The invention will be explained in detail referring to the attached drawings. The drawing shows an example of the apparatus to control the blowing the high-temperature reducing gas into a blast furnace automatically. High-temperature reducing gas is produced by the partial oxidation of .heavy oil with oxygen and steam.

In the FIGURE, 1 is a device for settling the supply amounts of raw materials (heavy oil, oxygen and steam), 2 is a raw material controlling device to control the supply amounts of raw materials to a cracking furnace, 4 is a furnace pressure gauge provided in a blast furnace 5, 6 is a pressure control valve provided in a reducing gas exhaust pipe line 7, 8 is a pressure gauge provided in said reducing gas exhaust pipe line 7, and 9 is a controller; and 10 is an intensive cooler for exhaust high-temperature gas, 11 is a cooler for blow-in gas, 12 are cut-off valves for branched gas pipe lines and 13 is a main gas pipe line.

Now, when an electric current is applied to the supply amount settling device 1, the pressure control valve 6 opens fully. Then, the supply amounts of raw materials to the cracking furnace 3 are settled, and the raw material controlling device 2 begins to work to supply definite amounts of raw materials, i.e., heavy oil, oxygen and steam, to the pre-heated cracking furnace 3. The production of high-temperature reducing gas is commenced and, at the same time, the signal of supply amounts settled is sent to the controller 9. On the other hand, the furnace pressure gauge 4 sends the pressure of the blast furnace to the controller 9. The producer gas pressure in the cracking gas furnace is measured by the pressure gauge 8, and the data is put in the controller 9. Calculating from the signals from the furnace pressure gauge.4, the pressure gauge 8 and the supply amount settling device 1, the controller 9 instructs the degree of opening to the pressure control valve 6 so that the producer gas has a desired pressure, i.e., a pressure 0.3 0.5 kg/cm higher than the blast furnace pressure; and when the operation of the cracking furnace 3 reaches to a stationary state, producing a definite amount of producer gas with a definite gas pressure, the controller 9 instructs the opening of cutoff valves provided in every branch pipe lines, and the blowing of high-temperature reducing gas into the blast furnace 5 is commenced.

At the same time when the blowing-in is commenced, the controller 9 controls the degree of opening of the pressure control valve 6 according to the signals from the furnace pressure gauge 4 and the producer gas pressure gauge 8 to maintain the pressure of high-temperature reducing gas in the cracking furnace as 0.3 0.5 kg/cm higher than the blast furnace pressure.

The blowing-in of high-temperature reducing gas is started from each of the branch pipe lines successively; and when no trouble is observed after a certain period since the blowing from all the branch pipe lines into the blast furnace 5 is completed, the controller 9 settles anew the upper limit of the producer gas pressure as 1.0 kg/cm higher than the furnace pressure. In this stage, the control valve 6 is shut completely. When the producer gas pressure exceeds the upper limit of said settled value during the blowing of high-temperature reducing gas into the blast furnace, the pressure control valve 6 is controlled to open. On the other hand, when high-temperature reducing gas is to be exhausted temporally according to the furnace condition, the controller 9 controls, based on the instruction of the blast furnace operator, the opening of the pressure control valve 6 so as to make the producer gas pressure as 0.2 0.3 kg/cm higher than the furnace pressure; and after the producer gas pressure reaches in the range abovementioned, every cut-off valves in the branch gas pipe lines are cut off successively.

When the blowing of the gas into the blast furnace from each of the branch pipe lines is to be stopped completely for a long period, the operation of the cracking furnace is stopped. In this case, the amounts of raw materials to be supplied in the supply amounts settling device 1 is settled as zero. Then the raw materia] controlling device 2 stops the supply of raw materials, and the pressure control valve 6 is opened by the instruction from the controller 9; and when the blowing-in pressure becomes under the settled range, the cut-off valves in all branch pipe lines are closed and the blowing-in .is stopped. The pressure control valve 6 is closed completely by cutting the electric current.

Instead of above-mentioned automatic control, the pressure control valve 6 and the cut-off valves 12 can be operated, prior to said automatic control, by the manual operation of the controller 9. The hand and automatic operations are exchanged by a switch. The control by the hand operation is applied when a special operation is needed besides the normal operation instructed by the controller 9. For instance, when the flow rate of high-temperature reducing gas blown in from each of the branch pipe lines differs each other and a specific inlet is particularly out of order, the computer is operated by hand. A part of the reducing gas is exhausted, all the cut-off valves except that of the branch pipe line out of order are closed to increase the blowing-in pressure of the gas, and the gas is forced to blow-in only through said inlet. Then the resistance (for instance, due to the lump of fine dust) at the tip of said inlet is expelled by the strong gas flow, and the norm ass e is resto ed.

n tea of operating by the above-mentioned control system, the cut-off valves in every branch pipe lines can be operated independently to give a stabilized blowingin of the gas.

As the reducing gas passing through the exhaust pipe line 7 is under a high temperature, the pressure gauge 8 and the pressure control valve 6 may preferably be of a heat resistant structure. It is also possible to lower the temperature of the high-temperature reducing gas by the direct contact of the exhaust gas with water in an intensive cooler 10, removing at the same time impurities contaminated in the gas.

In conclusion, by the use of the apparatus of this invention, it is possible to blow high-temperature reducing gas into a blast furnace always under a stabilized condition corresponding to the condition of the blast furnace operation. The effect of this invention is quite remarkable, and its operation requires no man power at all.

What is claimed is:

1. An apparatus for blowing high-temperature reducing gas into a blast furnace comprising a device for settling the supply amounts of raw materials such as hydrocarbons, a raw material controlling device to control the supply amounts of hydrocarbons, oxygen (or air) and steam to a cracking furnace according to the signal of said supply amount settling device, a furnace pressure gauge provided in the blast furnace, a cut-off valve for branch pipe gas, a pressure control valve provided in a reducing gas exhaust pipe line, a producer gas pressure gauge provided in an inlet pipe line of said pressure control valve, and an indicator controller to calculate and instruct the degree of opening of said pressure control valve according to the signals from said supply amount settling device, the furnace pressure gauge and the producer gas pressure gauge, and also calculate and instruct the opening and closing of the cut-off valve for branch pipe gas.

2. An apparatus for blowing high-temperature reducing gas into a blast furnace comprising a device for settling the supply amounts of raw materials such as hydrocarbons, a raw material controlling device to control the supply amounts of hydrocarbons, oxygen (or air) and steam to a cracking furnace according to the signal of said supply amount settling device, a computer to settle the pressure of producer gas by hand, a furnace pressure gauge provided in the blast furnace, a cut-off valve for branch pipe gas, a pressure control valve provided in a reducing gas exhaust pipe line, and a producer gas pressure gauge provided in an inlet pipe of said pressure control valve. 

1. An apparatus for blowing high-temperature reducing gas into a blast furnace comprising a device for settling the supply amounts of raw materials such as hydrocarbons, a raw material controlling device to control the supply amounts of hydrocarbons, oxygen (or air) and steam to a cracking furnace according to the signal of said supply amount settling device, a furnace pressure gauge provided in the blast furnace, a cut-off valve for branch pipe gas, a pressure control valve provided in a reducing gas exhaust pipe line, a producer gas pressure gauge provided in an inlet pipe line of said pressure control valve, and an indicator controller to calculate and instruct the degree of opening of said pressure control valve according to the signals from said supply amount settling device, the furnace pressure gauge and the producer gas pressure gauge, and also calculate and instruct the opening and closing of the cut-off valve for branch pipe gas.
 2. An apparatus for blowing high-temperature reducing gas into a blast furnace comprising a device for settling the supply amounts of raw materials such as hydrocarbons, a raw material controlling device to control the supply amounts of hydrocarbons, oxygen (or air) and steam to a cracking furnace according to the signal of said supply amount settling device, a computer to settle the pressure of producer gas by hand, a furnace pressure gauge provided in the blast furnace, a cut-off valve for branch pipe gas, a pressure control valve provided in a reducing gas exhaust pipe line, and a producer gas pressure gauge provided in an inlet pipe of said pressure control valve. 